octeon_rnd.c revision 210311
1/*- 2 * Copyright (c) 2010 Juli Mallett <jmallett@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD: head/sys/mips/cavium/octeon_rnd.c 210311 2010-07-20 19:25:11Z jmallett $ 27 */ 28 29#include <sys/cdefs.h> 30__FBSDID("$FreeBSD: head/sys/mips/cavium/octeon_rnd.c 210311 2010-07-20 19:25:11Z jmallett $"); 31 32#include <sys/param.h> 33#include <sys/systm.h> 34#include <sys/bus.h> 35#include <sys/clock.h> 36#include <sys/kernel.h> 37#include <sys/lock.h> 38#include <sys/module.h> 39#include <sys/random.h> 40 41#include <contrib/octeon-sdk/cvmx.h> 42#include <contrib/octeon-sdk/cvmx-rng.h> 43 44/* 45 * XXX 46 * random_harvest(9) says to call it with no more than 16 bytes, but at least 47 * safe(4) seems to violate that rule. 48 */ 49#define OCTEON_RND_WORDS 2 50 51struct octeon_rnd_softc { 52 uint64_t sc_entropy[OCTEON_RND_WORDS]; 53 struct callout sc_callout; 54}; 55 56static void octeon_rnd_identify(driver_t *drv, device_t parent); 57static int octeon_rnd_attach(device_t dev); 58static int octeon_rnd_probe(device_t dev); 59static int octeon_rnd_detach(device_t dev); 60 61static void octeon_rnd_harvest(void *); 62 63static device_method_t octeon_rnd_methods[] = { 64 /* Device interface */ 65 DEVMETHOD(device_identify, octeon_rnd_identify), 66 DEVMETHOD(device_probe, octeon_rnd_probe), 67 DEVMETHOD(device_attach, octeon_rnd_attach), 68 DEVMETHOD(device_detach, octeon_rnd_detach), 69 70 { 0, 0 } 71}; 72 73static driver_t octeon_rnd_driver = { 74 "rnd", 75 octeon_rnd_methods, 76 sizeof (struct octeon_rnd_softc) 77}; 78static devclass_t octeon_rnd_devclass; 79DRIVER_MODULE(rnd, nexus, octeon_rnd_driver, octeon_rnd_devclass, 0, 0); 80 81static void 82octeon_rnd_identify(driver_t *drv, device_t parent) 83{ 84 BUS_ADD_CHILD(parent, 0, "rnd", 0); 85} 86 87static int 88octeon_rnd_probe(device_t dev) 89{ 90 if (device_get_unit(dev) != 0) 91 return (ENXIO); 92 93 device_set_desc(dev, "Cavium Octeon Random Number Generator"); 94 return (0); 95} 96 97static int 98octeon_rnd_attach(device_t dev) 99{ 100 struct octeon_rnd_softc *sc; 101 102 sc = device_get_softc(dev); 103 callout_init(&sc->sc_callout, CALLOUT_MPSAFE); 104 callout_reset(&sc->sc_callout, hz * 5, octeon_rnd_harvest, sc); 105 106 cvmx_rng_enable(); 107 108 return (0); 109} 110 111static int 112octeon_rnd_detach(device_t dev) 113{ 114 struct octeon_rnd_softc *sc; 115 116 sc = device_get_softc(dev); 117 118 callout_stop(&sc->sc_callout); 119 120 return (0); 121} 122 123static void 124octeon_rnd_harvest(void *arg) 125{ 126 struct octeon_rnd_softc *sc; 127 unsigned i; 128 129 sc = arg; 130 131 for (i = 0; i < OCTEON_RND_WORDS; i++) 132 sc->sc_entropy[i] = cvmx_rng_get_random64(); 133 random_harvest(sc->sc_entropy, sizeof sc->sc_entropy, 134 sizeof sc->sc_entropy * 8, 0, RANDOM_PURE); 135 136 callout_reset(&sc->sc_callout, hz * 5, octeon_rnd_harvest, sc); 137} 138